Fig. 17
From: Congenital systemic venous return anomalies to the right atrium review
a Variable hemiazygos drainage schematic. Independent drainage of the hemiazygos vein to the SVC, via the accessory hemiazygos vein→left superior intercostal vein→left brachiocephphalic vein path. b Variable hemiazygos drainage imaging. Contrast-enhanced CT scan showing independent drainage of the hemiazygos vein (triangle) to the left brachiocephphalic vein, via the left superior intercostal vein (arrow), with normal drainage of the azygos vein via the azygos arch (asterisk)